In general, a coil spring or an air spring called a suspension spring elastically supporting a vehicle body is interposed between a vehicle body and a wheel in a vehicle. The suspension spring absorbs an impact caused by irregularity on a road surface.
In a vehicle, if there are many loads or occupants, a compression amount of the suspension spring becomes larger. As a result, a vehicle height might become too low. On the other hand, if the loads or occupants are fewer, the compression amount of the suspension spring becomes smaller. As a result, the vehicle height might become too high. Thus, as disclosed in JP2010-149550A, a vehicle height adjustment device for adjusting a vehicle height is mounted on a vehicle in some cases. In the vehicle height adjustment device, a jack chamber filled with an operating fluid supports a spring receiver supporting a one-side end portion of the suspension spring. Then, by supplying/discharging the operating fluid into/out of this jack chamber by a pump, the spring receiver is elevated up/down so as to adjust the vehicle height.